A. I. Ivanov
Republican Саnсеr Center of the Republic of Tatarstan Ministry of Health; Institute of Fundamental Medicine and Biology, Kazan Federal University; Kazan State Medical Academy – Branch of Russian Medical Academy of Continuous professional Education
Russian Federation

 MD, PhD, Assistant Lecturer, Department of Endoscopy, General and Endoscopic Surgery; Endoscopist; Associate Professor, Department of Fundamentals of Clinical Medicine

29, Siberian tract, 420029, Kazan, Russia

76, Karl Marx Street, 420012, Kazan, Russia 

 36, Butlerova Street, 420012, Kazan, Russia

V. A. Popov
Republican Clinical Hospital of the Republic of Tatarstan Ministry of Health
Russian Federation

 MD, Endoscopist 

138, Orenburg tract, 420064, Kazan, Russia 

M. V. Burmistrov
Institute of Fundamental Medicine and Biology, Kazan Federal University; Kazan State Medical Academy – Branch of Russian Medical Academy of Continuous professional Education; Republican Clinical Hospital of the Republic of Tatarstan Ministry of Health
Russian Federation

 MD, DSc, Professor of the Department of Oncology, Radiology and Paliative Medicine; Deputy Physician; Head of the Department of Surgical Diseases,
Department of Fundamentals of Clinical Medicine, Institute of Fundamental Medicine and Biology 

 76, Karl Marx Street, 420012, Kazan, Russia 

 36, Butlerova Street, 420012, Kazan, Russia 

 138, Orenburg tract, 420064, Kazan, Russia